Electrophysiology Research

Everyone in Nova Scotia knows someone - an uncle, a grandfather, or perhaps a family friend, who died suddenly. Often this affects the elderly, but it can also affect the young. People who have scar in their heart, usually from a prior heart attack (perhaps years before) - are at highest risk. Sudden cardiac death is the leading cause of death in Canada, affecting 50,000 people per year in Canada - more than breast cancer, lung cancer and AIDS combined. The Heart Rhythm Service at the QEII Health Science Centre is actively working on how to treat and prevent this. The core of this effort is the Cardiac Electrophysiology Laboratory, where heart rhythm specialist clinician researchers can implant pacemakers and defibrillators, conduct cardiac electrophysiology studies and perform catheter ablation procedures - continuing their work to investigate means to improve all of these. 

The ICD Database: Is everyone who needs treatment getting it?

Dr. Ratika Parkash has become well known for her work in researching access to life-saving therapy. Her early studies demonstrated that only 13 percent of patients who might have been eligible to be treated with an implantable defibrillator actually received one. Patients who have life-threatening heart rhythm disorders, or who are at high risk to develop one, are best treated with an implantable cardiac defibrillator (ICD). These devices can monitor the heart beat 24 hours a day, and if a dangerous heart rhythm develops, they can intervene early and shock the heart back to normal. This early intervention has been shown to save lives and protect people from sudden cardiac death. One of the major efforts of the heart rhythm service has been spearheaded by Dr. Ratika Parkash to develop a database which includes every patient who is referred to be evaluated for an ICD. Studying patterns of referral, device therapy, and outcomes can help us understand who benefits from this treatment, and how to reach those who have not been referred. This work has extended to the national level, at which Dr. Ratika Parkash now co-chairs the Canadian Device Advisory Committee which provides rapid communication between Canadian heart rhythm specialists on ICD and pacemaker-related issues and facilitates several Canadian research initiatives.

The VT Ablation Database: A Cure for Lethal Arrhythmias?

Dr. John Sapp focuses on the treatment of one of the most dangerous heart rhythm abnormalities: Ventricular Tachycardia (VT). His particular interest has been in understanding this heart rhythm and improving methods for catheter ablation of VT. Catheter ablation is a procedure performed in the Cardiac Electrophysiology Laboratory in which wires are passed up through blood vessels into the heart, and directed to the areas of heart scar which cause arrhythmias. One of the wires has a special tip capable of cauterizing (“ablating”) the troublesome area and getting rid of the arrhythmia. Catheter ablation to get rid of VT is one of the most difficult procedures to do in all of Cardiac Electrophysiology. Dr. John Sapp has been responsible for developing a database of all ablation procedures for VT performed at the QEII. This work has demonstrated that ablation can be effective for VT even in the most challenging circumstances, when the rhythm is at its most dangerous and in the most scarred hearts. In many cases, it can permit discontinuation of harsh drugs. 

Novel Methods for VT Ablation: Can we do it better?

VT is one of the most dangerous heart rhythms and is the most common cause of sudden cardiac death and finding a universally applicable cure would revolutionize its management. Catheter ablation for VT is very difficult and the search for methods to make it easier and more successful is critical. Dr. John Sapp is working with collaborators at Harvard and in industry to bring a new kind of ablation catheter to clinical use in the Cardiac Electrophysiology Laboratory. This catheter has a special tip that can reach deeper into the heart muscle to ablate deeper scars - one of the most important limitations of catheter ablation of VT. This research could change the way this procedure is performed.

Another major area of research for Dr. John Sapp is for methods to find scars in the heart, and determine which ones are causing dangerous heart rhythms (VT). While a regular ECG has 10 electrical patches placed on the skin of the limbs and chest, he has been studying methods to use 120 patches placed over the entire front and back of the chest to determine where a person’s VT is coming from. In close collaboration with colleagues in Physiology and Biophysics at Dalhousie University, this research has demonstrated that the electrical activity on the surface of the heart can be imaged from the skin surface. The simultaneous recording of 120-lead ECGs while recording with a catheter on the inner and outer surface of the heart in the Cardiac Electrophysiology Laboratory could become a new way to help clinicians be more successful at catheter ablation of VT. Further research is ongoing in ways to use this same electrical imaging technology to improve treatments for heart failure - finding optimal ways to activate the heart for maximal efficiency. 

Research In Inherited Heart Disease: The Age of Genetics

Dr. Martin Gardner was one of the first heart rhythm specialists in Canada to recognize the importance of genetics in heart rhythm abnormalities. Many people think of heart disease as a “lifestyle disease” - as a problem caused by smoking and obesity. But this isn’t really fair. To be sure, lifestyle can have a very important influence on heart health, but many heart problems are inherited, just like hair colour and eye colour. What should we do if a young person dies suddenly? Are his/her brothers and sisters at risk? What about children? Dr. Martin Gardner has initiated the inherited heart disease clinic, and is now working with Dr. Chris Gray to look after not just individual patients, but their families. This clinic includes a heart rhythm specialist, a dedicated nurse, a geneticist, a pediatric cardiologist and a genetics counselor, all working together to care for affected patients, to make complex diagnoses, to minimize the risk of dangerous heart rhythms, and to provide counseling for future generations. Dr. Martin Gardner is actively researching methods to best investigate patients with a family history of sudden arrhythmic death in the young. His work has shown that with a systematic investigative approach, family members with otherwise unsuspected risk can be identified, treated, and rescued. 

The Link Between Heart Failure and Sudden Cardiac Death: The AIRCRAFT study

Dr. John Sapp and Ratika Parkash are working together with collaborators across Canada on an investigation into how heart failure causes sudden cardiac death. We know that the risk of dangerous heart rhythms is worse in the presence of heart failure, but no one has yet been able to clearly show whether arrhythmias worsen heart failure, or whether heart failure worsens arrhythmia, nor whether we can do anything about this. AIRCRAFT (Abnormalities In Rhythm in the Cardiac Resynchronization in Ambulatory heart Failure Trial) is a substudy of a major international randomized clinical trial of different types of defibrillators for patients with heart failure. AIRCRAFT uses the highly detailed computer memory in ICDs to record dangerous heart rhythms in heart failure patients and will study whether treating heart failure can reduce abnormal heart rhythms. This grant-funded research was awarded the prize for highest rated research grant application by the Heart and Stroke Foundation Nova Scotia. 

Randomized Clinical Trials Led In Halifax: Getting the Definitive Answers!

A clinical trial is the most rigorous way to answer a clinical question in medicine. In a clinical trial, patients are randomly allocated to get one of two specific competing treatments, and the outcomes are studied. This kind of study comes out of more basic research into what causes things like abnormal heart rhythms, and provides the final answer into what treatments are the most effective. The Canadian heart rhythm community has a long history of effective collaboration in multicentre clinical trials, and the Heart Rhythm team at the QEII has played a significant role in many landmark research in managing heart rhythm abnormalities, some of which have completely changed the way that patients are treated around the world. In cooperation with colleagues across Canada and internationally, the Heart Rhythm Team at the QEII continues to work on several questions:Dr. Magdy Basta and Chris Gray are currently involved in research to find better methods to prevent stroke in patients with heart rhythm abnormalities, as well as methods to use ICDs to improve heart failure; Dr. John Sapp is taking part in research investigating which kind of ICD is best for heart failure patients, and Dr. Parkash is involved in investigating better treatments for patients who faint.

Dr. John Sapphas begun an international randomized clinical trial comparing catheter ablation for VT to drug therapy. This includes collaborating centres all across Canada, as well as in the US and Switzerland. This study, based out of the QEII, will be the first ever to investigate this problem, and will provide the definitive answer about how patients with VT should be treated for heart rhythm specialists all around the world. This major undertaking will be completed over the next five years.

Dr. Ratika Parkash has begun a multicentre cross-Canada study examining whether aggressively treating blood pressure can improve outcomes for patients who undergo catheter ablation for a very common arrhythmia, atrial fibrillation. This study, led out of the QEII, has the potential to change practice around the world, for what is rapidly becoming one of the most common types of catheter ablation procedures.